Daily regression parameters k and d can be taken from Figures 7 and 8 to compute ρ_sim using the HS data of a certain day as input. As a first model test, all HS records of the station data are used to simulate ρ_sim (Equation (4)). Values of the regional offset parameter OS_reg are shown in Table 3. OS_reg is highest in regions where deep snow covers are commonly observed (e.g., region 1). In both elevation zones, absolute errors (AE) of SWE are lower than absolute errors of ρ since this approach benefits from observed HS as input (Figure 9). The curves of the relative mean absolute errors (MAE_rel) of SWE are also calculated using the ±16 day window. MAE_rel is constantly higher in the lower elevation zone and both error curves decrease over the course of the season (except April/May <1,400 m a.s.l.).